Chewing tobacco. I quit once for a year after having chewed for about 6 years. I went cold turkey....it wasn't really that difficult. I think it helped that at the time I had just moved into an apartment on my own, so the whole living alone thing was new to me. When I was in between moving from that apartment to a house, I had to live with my parents for a few weeks, and I started chewing again. I recently quit cold turkey again just because it's a disgusting habit. I don't have withdraw or anything, I think I chewed because I would do it when I got home from work during my "cool down" period. Now I just listen to music, or play a video game.